"I'm learning to say 'y'all' and I like grits, and strange things are happening to me!" the former Massachusetts governor added.
Critics were quick to jump on Romney's comments as just a poor attempt to connect to Southern voters, something observers have said he has struggled to do so far in his campaign.
MSNBC morning show host Joe Scarborough, who was born in Georgia, suggested Friday morning that Romney's Southern impression wasn't fooling any true Southerner.
Romney jokes he's becoming an "unofficial southerner" & Joe jokes "Nobody believes he's one of us. Nobody." #morningjoe— Morning Joe (@Morning_Joe) March 9, 2012
Romney on Thursday called the Mississippi and Alabama primaries "a bit of an away game" for him, but he still hoped to pick up some delegates in the two Deep South states voting next week.
"That, of course, is what this is all about: getting the delegates necessary to become the nominee," he said.
McCain, who was the 2008 GOP presidential nominee, endorsed Romney as the nominee in early January.